JPH011083A - Object image synthesis device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an object image synthesis device that synthesizes images for displaying objects.

[Conventional technology]

A method called the ray search method is used to synthesize digital images for displaying objects. In this method, the path of the light ray from the light source to the viewpoint is traced in the opposite direction, a process is performed to determine the intersection between the light ray and the object, and the brightness of each pixel making up the image is calculated based on the result. An example of this ray search method can be found in Information Processing Society of Japan Transactions, Vol. 25, No. 6, Hiroshi Deguchi, Hitoshi Nishimura, Hiroshi Yoshimura, Toru Kawada, Isao Shiro, and Hiroshi Omura, in the paper "Computer Graphics System L.
``Technique for accelerating image generation in INKS-1''.

In order to perform image generation using such a ray search method at high speed, the space in which the object is defined is divided into multiple regions, each region is assigned to one computer, and each computer is Methods have been proposed for processing light rays passing through a region. Details of this method can be found in Computer Graphics (Complter
Graphics, Volume 18, Issue 3, Mark Dippc, John Swensen, Paper: An Adaptive Subdivision Algorithm and Parallel Architecture for Realistic Image Synthesis.
5ubdivision AIgorithg*an
dParallel Architecture for
r Realistic 1magI! 5ynthes
is)”. In the method described above, the space is first divided into a plurality of rectangular parallelepiped regions, and each region is assigned to one computer. Next, each computer stores data on objects included in the assigned rectangular parallelepiped area. Each computer then performs an intersection determination process between a light beam passing through the area and an object. Through this intersection determination processing, when the object and the light ray intersect, reflection and transmission processing on the object surface is performed. Information about rays that do not intersect objects within that region is transferred to computers assigned to adjacent regions. When performing such processing, there is a possibility that there will be considerable variation in the amount of processing performed by each computer. That is, a computer assigned to an area containing many objects has a very large amount of processing to do, while a computer assigned to an area containing no objects may not be able to process much at all.

In order to reduce such variations in load between computers, a method has been proposed in which the vertices of a region divided into rectangular parallelepipeds are arbitrarily moved to change the volume and shape of the region. That is, by moving the vertices, the amount of computer processing allocated to the area whose volume has decreased is reduced. Then, the processing for that amount is shared with the computer assigned to the area whose volume has increased due to the movement of the vertex. In this way, the load is redistributed among the computers.

[Problems to be Solved by the Invention] In such conventional load redistribution methods, the shape of the region changes in various ways because the load is redistributed by moving the vertices of the region. That is, since the deformation is due to the movement of vertices, the shape of the region is kept as a hexahedron, but the orientation and shape of each boundary surface of the region can be arbitrary. This causes the following problems.

First, when transmitting light beam information from a divided region to an adjacent region, the region to be transferred is determined by determining the intersection between the boundary surface of the region and the light beam. However, since the orientation and shape of each boundary surface of the region are arbitrary, the processing amount of this intersection determination process becomes extremely large. Therefore, there is a problem that the overall processing time becomes slow.

Second, when the shape of a region is changed, information about objects included in the region must also be changed. That is, in the case of a region whose volume has decreased, there is a possibility that some objects that were included in the region before the change are no longer included in the region after change 1hi. Furthermore, in the case of a region whose volume has increased, there is a possibility that a new object will be included in that region. When changing object information like this,
Since the shapes of the regions vary, there is a problem in that the processing amount and processing time required to determine objects included in the regions become extremely large.

As described above, the conventional method of redistributing the load by moving the vertices of the area has the problem that the redistribution requires a very large amount of processing, and the effect of the redistribution cannot be sufficiently obtained.

An object of the present invention is to simplify the process of changing the area shape for load redistribution, thereby reducing the processing involved in changing the area shape and sufficiently increasing the effect of redistribution. An object of the present invention is to provide an object image synthesis device.

[Means for solving problems]

The object image synthesis device of the present invention divides a space in which the object is defined into an initial ray generation section that generates information on a plurality of rays passing through each pixel from a viewpoint, and an object information setting section that sets object information. A plurality of luminances in which the brightness of the pixel is calculated by performing intersection determination processing between a light ray passing through this region and an object included in the region in charge of one region among the plurality of regions generated by It consists of a calculation unit and an image storage unit that stores the brightness calculated by the brightness calculation unit as an image, and the brightness calculation unit has an image generated by dividing the object definition space by a plane perpendicular to the coordinate axes. area information storage means for storing the range of the area in charge of the brightness calculation unit among the plurality of areas; and initial storage means for storing the range of the area in charge given as an initial value as the range of the initial area of the brightness calculation unit. and load determination means for determining the load of the brightness calculation unit, and mutual communication between the brightness calculation unit and an adjacent brightness calculation unit that is in charge of an area adjacent to the area in its duty in a direction parallel to each coordinate axis. The direction of the area in charge of the adjacent brightness calculation unit in which the load of the adjacent brightness calculation unit obtained through the communication means and the mutual communication unit is maximum is determined as the direction of expansion of the area in charge of the brightness calculation unit, and the load is increased. a direction determining means for determining the direction of the area in charge of the adjacent brightness calculation unit that is the minimum as a reduction direction of the area in charge of the brightness calculation unit; a load on the adjacent brightness calculation unit where the load is maximum; and a load on the brightness calculation unit. expansion determining means for determining whether or not to expand the area in charge of the brightness calculating section in the expansion direction determined by the direction determining means by comparing the load of the adjacent brightness calculating section with the load of the adjacent brightness calculating section that minimizes the load; The load of the brightness calculation section is compared, and the range of the initial area stored in the initial area storage means is compared with the range of the area in charge stored in the area information means, and based on these comparison results, the reduction determining means for determining whether or not to reduce the area in charge in the reduction direction determined by the direction determining means; and in the enlargement direction determined by the direction determining means based on the decisions of the expansion determining means and the reduction determining means. and area changing means for changing the range of the responsible area stored in the area information storage means in order to expand the responsible area and reduce the responsible area in the reduction direction determined by the direction determining means. .

[Effect]

A load redistribution method in the present invention will be described. Each brightness calculation unit is assigned one area out of a plurality of areas generated by dividing the object definition space along a plane perpendicular to the coordinate axes, as the area in charge of that brightness calculation unit. The range of this area in charge is stored in area information storage means provided in the brightness calculation section.

Further, the range of the assigned area given as the initial value is stored in the initial area storage means as the initial area range of each brightness calculation section.

Here, among the areas adjacent to the area in charge of this brightness calculation unit, the six brightness calculation units in charge of areas in the direction parallel to each coordinate axis (x, y, z axis) are referred to as adjacent brightness calculation units. The load of each brightness calculation unit is determined by the load determination means,
It is transferred to six adjacent brightness calculation units via mutual communication means.

Then, the direction determining means selects the maximum load among the loads of the six adjacent brightness calculation units obtained through the mutual communication means, and determines the connection method of the adjacent brightness calculation units that have the maximum load.
Determine the direction of expansion of the area of responsibility. At the same time, the minimum load is selected from among the loads of the six adjacent brightness calculation units, and the connection method of the adjacent brightness calculation units resulting in this minimum load is determined as the direction of reduction of the area in charge. And the direction determining means is
The maximum load is outputted to the enlargement determining means, the minimum load 3 is outputted to the reduction determining means, and the enlargement direction and the reduction direction are further outputted to the area changing means.

Next, the expansion determining means compares the load of the brightness calculating section determined by the load determining means with the maximum load of the adjacent brightness calculating section outputted from the direction determining means. If the load of this brightness calculation unit is smaller than the maximum load of the adjacent brightness calculation unit, and the absolute value of the difference between the two is greater than a given threshold, the area in charge of the adjacent brightness calculation unit with the maximum load It is determined that the area in charge of this brightness calculation unit is to be expanded in the direction of . Furthermore, if the conditions of the load comparison result do not hold, it is determined not to expand the area in charge of this brightness calculation section.

At the same time, the reduction determining means compares the load of the brightness calculating section determined by the load determining means with the minimum load of the adjacent brightness calculating section output from the direction determining means. Further, the reduction determining means compares the range of the initial area stored in the initial area storage means and the range of the area in charge stored in the area information storage means.

If the load of this brightness calculation unit is larger than the minimum load of the adjacent brightness calculation unit and the absolute value of the difference between the two is larger than the given threshold, the area in charge of the adjacent brightness calculation unit with the minimum load It is determined that the area in charge of this brightness calculation unit is to be reduced in the direction of . However, based on the comparison result between the assigned area and the initial area, if reducing the assigned area would result in the assigned area becoming smaller than the initial area, it is determined not to reduce the assigned area. Also, if the conditions of the load comparison result do not hold, it is determined not to reduce the area in charge of this brightness calculation unit.

Finally, the area changing means changes the range of the area in its duty stored in the area information storage means in accordance with the decisions made by the expansion determining unit and the reduction determining unit, and executes expansion and reduction of the area in its duty. In this way, the load is redistributed between the brightness calculation unit and its adjacent brightness calculation units by expanding or contracting the assigned area based on the load comparison results.

〔Example〕

FIGS. 1(a) and 1(b) are block diagrams showing an object image synthesis device as an embodiment of the present invention, and FIG. 1(a) is a
Figure 1 (b) is an overall configuration diagram showing the entire object image synthesis device.
) is a configuration diagram showing the detailed configuration of the brightness calculation section. As shown in FIG. 1 (a), an initial ray generating section 1 is provided which generates information on a plurality of rays passing through each pixel of an image to be synthesized from a preset viewpoint. An object information setting unit 2 is provided for setting object information.Furthermore, it is in charge of one area out of a plurality of areas generated by dividing the space in which the object is defined. A plurality of brightness calculation units 3 are provided that calculate the brightness of each pixel by performing a process of determining the intersection of a light beam passing through the area with an object included in the corresponding area.

An image storage section 4 is provided to store the luminance calculated by the luminance calculation section 3 as an image. This image storage unit 4
sets all luminances to 0 before compositing images. A connection line 5 is provided for transmitting information between the initial light generation section 1, the object information setting section 2, the plurality of brightness calculation sections 3, and the image storage section 4. An information manpower 6 is provided for inputting information via this connection line 5, for example from a keyboard. As shown in FIG. 1(b), the brightness calculation unit 3 is provided with mutual communication means 31 that communicates with the brightness calculation units 3 in charge of areas adjacent in six directions. Further, a communication means 32 for communicating via the connection line 5 is provided. moreover,
A connection line 101 is provided for transmitting information within the brightness calculation unit 3.

FIG. 2 is an explanatory diagram showing a method of calculating the brightness I of the pixel p(i,j). As shown in FIG. 2, in the ray search method, from the light source to the pixel p (i.

j) Reverse the path of the ray that passes through and reaches viewpoint E,
The brightness of pixel p(i,j) is calculated.

Here, the brightness ■ of the pixel p (i, j) will be referred to as the brightness of the light ray R generated in the opposite direction from the viewpoint E through the pixel p (i, j). The brightness ■ of this light ray R is the pixel p
This is the intensity I of the light that passes through (i, j) and enters the viewpoint E. The brightness I of the light ray R is calculated by the following formula.

River=ref-I'+dif ・(LL) ・It
.

ref: Reflection coefficient of object O dif: Diffusion coefficient of object 0 I': Incident light intensity from the R' force direction L: Incident light intensity from the light source M: Unit normal vector of the surface of object O π°: R
Specular reflection direction vector RL: Direction vector of the light source Calculating these two incident light intensities I' and TL becomes 2
Two light rays R' and RL are generated. Further, the coefficients of I' and IL for determining the brightness I are set as the attenuation rate G' and OL of the light rays R' and RL. That is, the ray R is attenuated by colliding with the object 0, and the rays R' and R
L is generated. These attenuation factors G', GL
G'=G-ref G: Attenuation rate of light ray R (=1). These attenuation rates G', G1. By using , the brightness of the light ray R , i.e., the pixel p(i.

The brightness I of j) is determined as follows.

I=G"・I'+GL・IL In this way, when new rays R' and RL are generated,
Information about the ray R is no longer necessary. Furthermore, as shown in FIG. 2, when the ray R' intersects the object O', rays R" and RL' are similarly generated. Their attenuation rates G" and G
L' is similarly calculated using the following formula.

ref': Reflection coefficient dif' at object 0°:
Diffusion coefficient N' of the object O゛: Unit normal vector of the surface of the object O° RL: Directional vector of the light source In this way, the attenuation rate G'' and GL' are multiplied by the attenuation rate G°. , the processing of the rays RL is the rays R, R'
It is different from. When the light ray RL intersects an object, the intersection point CP becomes a shadow of the object and cannot receive the irradiation light from the light source. Therefore, the brightness IL of the light ray RL is zero. If ray RL does not intersect any object, then
The brightness IL of the light ray RL is the brightness of the light source. In this way, the rays R and R' heading towards the object and the ray RL heading towards the light source
Since they are treated differently, it is necessary to distinguish between the types of rays. Therefore, a type C is set for the light ray R to distinguish the type of light ray. This type C is given a value of 0 when the ray R is directed toward an object, and 1 when the ray R is directed toward a light source. As shown in FIG. 2, a ray of light directed toward an object generates a new ray of light directed toward the object each time it collides with an object. Therefore, in order to calculate the luminance (2) of one pixel p, it may be necessary to process many light rays. However, each time the light ray collides with an object, it is attenuated, so as the number of collisions increases, the effect of the light ray on the luminance (■) becomes almost negligible. Therefore, in order to limit the number of collisions of the ray R, a number T is set for the ray R. This number T indicates the number of possible collisions of the ray R. When a ray R with a number of times T collides with an object and a ray R' directed towards the object is generated, the number T' of the ray R' is (T-1
'). If a ray R whose number of times T is 0 collides with an object, a ray R' directed toward the object is not generated, but only a ray RL directed toward the light source is generated. In addition,
In FIG. 2, there is only one light source L1, but if a plurality of light sources L1 (i=1.2, . . . ) exist, it is necessary to generate light rays directed to all the light sources L1.

By the way, in the case of the light ray RL heading toward the light source, no new light ray is generated even if it intersects with an object, as described above, so
The number of times T as information about the light source RL has no meaning. Therefore, when a plurality of light sources L+ exist, the number i of the light source is set as the number of times T of the light ray RL. By setting the number of times T of the light rays RL in this way, even if there are multiple light sources, the light source L to which each light ray RL is directed
Since the number i of l is known, the process can be performed correctly. Also, here, for simplicity, only reflection on the surface of the object was considered. If we also consider the transmission of objects,
It is sufficient to generate a light beam in the transmission direction at the intersection of the object and the light beam R.

However, this type of ray is a ray directed toward an object,
If it is processed in the same manner as the above-mentioned ray R°, the transmission of the object can be accurately expressed.

FIG. 3 is an explanatory diagram showing information on the light ray R that should be set when the light ray R is generated. When the ray R is generated as shown in FIG. 3, the information about the ray R is the starting point position coordinates (S,) of the half-line indicating the ray R.

Sy, S2) and direction (dX, y, d2) are set. Furthermore, the pixel p(i,
The position (i, j) of j) is also set as information on the ray R. Furthermore, the attenuation rate G of the light ray R, the number of times T of the light ray R, and the type C of the light ray R are also set as information about the light ray R.

FIG. 4 is a diagram for explaining the operation of the initial light beam generating section 1.
It is an explanatory diagram. As shown in FIG. 4, the initial beam generating section 1
, a light ray R is generated on the extension of a half straight line starting from the viewpoint E and passing through each pixel p(i, j) constituting the image P. For this purpose, the information input unit 6 inputs the position coordinates (E, , E
y.

E,) is input. Further, as information defining the image P to be synthesized, a parameter indicating the range of the plane of the image fla P is input from the information input unit 6. The initial light beam generating section 1 generates information about the light beam R based on these parameters. An example of a method for finding a half-line indicating this ray R is the Tee and Whitted (T, Whitted) method.
), Communication of NCM (C
communication or ACM), No. 23
Volume, No. 6, pp. 343-349, the article "An Improved Illumination Model for Shaped Display"
Illumination Model for Sh
Aded Display) J. Next, among the intersections between this half-line and the object definition space, find the positional coordinates (SX, Sy, S2>) of the intersection closest to the viewpoint.This positional coordinate (S, ,S,,S,> is The starting point position coordinates (SX, Sy, S2) of the ray R are the starting point of the ray R. In other words, the position where the ray R first enters the object definition space is the starting point of the ray R. Also, the direction from the viewpoint E toward the pixel p is The direction of the ray R is ((iX, dy, dz). Furthermore, the position (t, j) of the pixel p(i, j) is set as the pixel position (i, j) of the ray R. Initial ray In the generating section 1, the attenuation rate G of the generated light ray R is set to 1, that is, it is not attenuated at all.
In this case, a preset constant value is given to the initial light beam generation section 1 from the information input section 6. Furthermore, as type C,
A value of O is given which indicates the rays directed towards the object. In the initial light beam generation unit 1, the light beam R having information is transmitted to the image P.
is generated corresponding to all pixels p(i,j), and is transferred to the brightness calculation unit 3.

FIG. 5 is an explanatory diagram showing object information set in the object information setting section 2. As shown in FIG. To simplify the explanation, the displayed object will be limited to a sphere, but the same method can be applied to display objects such as polyhedrons and free surfaces. As shown in FIG. 5, object information is input from the information input section 6 and set in the object information setting section 2. As shown in FIG.

The information on the object i that is set is the object number nl for distinguishing the object i + the center coordinates of the sphere (X, as the object).

yl + Z l ) + radius r+, diffusion 1 series dif indicating the material of the 70 bodies, and reflection coefficient ref+. Further, as information indicating the circumscribed area of the object i, the range of the smallest rectangular parallelepiped including the object is set.

FIG. 6 is an explanatory diagram showing a circumscribed region of a sphere as an object. As shown in FIG. 6, the circumscribed area of object i is the range in the X direction (X + X 14) + the range in the X direction (3'
I-+ yI') + Z-direction range (z H-, z
It is a rectangular parallelepiped indicated by ++). Find these values using the following equations.

xl-=　　　　　Xl　　　-r.

X1+ ” XI + rly I-=
yt1”+yl+”
yl + rlZi−= Zl
−r +Zl◆=Zl+rl FIG. 7 is an explanatory diagram showing information on the light source set in the object information setting section 2. To simplify the explanation, the explanation will be limited to point light sources, but the same method can be used when drawing various types of illumination light such as parallel rays and spotlights. As shown in FIG. 7, information on a light source for illuminating an object is input from the information input section 6 and set in the object information setting section 2. The information on the light source that is set is the position coordinates (Xl,'!+,Zl) of the point light source i+the brightness ILI of the light source. This luminance IL+ is a real value between 0 and 1. This luminance rt+ value indicates the brightness of the light source, and when it is 1, it is the brightest, and when it is 0, it is a clear light source. The object information and light source information set in this way are
The information is transmitted from the object information setting section 2 to the brightness calculation section 3 via the connection line 5.

FIG. 8 is an explanatory diagram showing a method of combining a plurality of brightness calculation units 3 into a three-dimensional array. As shown in FIG. 8, the brightness calculation units 3 are connected in a three-dimensional array via mutual communication means 31 provided within the brightness calculation units 3. That is, each brightness calculation section 3 is connected to the brightness calculation sections 3 on both sides in the x, y, and z directions, and can mutually transmit information with these brightness calculation sections 3. Here, x, y.

The a, b, and c-th brightness calculation units 3 in two directions are (a.

b, c) If we call it the brightness calculation unit 3, (a.

b, c) The brightness calculation unit 3 calculates (a-1, b, c).

(a+1. b, c), (a,
b-1, c), (a.

b+1. c), (a, b, c-1>, (a, b.

C+1) Connected to the brightness calculation section 3. Further, the brightness calculation units 3 are arranged in A, B, and C pieces in the x, y, and z directions in the figure, respectively, and the total number of brightness calculation units 3 is as follows: D=A-B-C.

FIG. 9 is an explanatory diagram showing a method of dividing a space defining an object into areas S assigned to each brightness calculation unit 3. As shown in FIG.

By planes perpendicular to one of the y and z coordinate axes,
Divide the object definition space into multiple rectangular parallelepiped regions. In this case, the number of areas in the X direction is A, and the number of areas in the X direction is B.
The division is performed so that the number of regions in the Z direction is C. And (a, b.

C) Allocate the 8th area in the X direction, the 5th area in the X direction, and the 0th area in the Z direction to the brightness calculation unit 3. Thereby, all the divided areas can be assigned to one brightness calculation unit 3, respectively. Moreover, by performing such allocation, the brightness calculation units 3 connected via the mutual communication means 31 are respectively in charge of adjacent areas.

10 and 11 are explanatory diagrams showing the contents of area information indicating the area S in charge of the brightness calculation unit 3.

As shown in FIG. 10, the area information storage means 33 provided in the brightness calculation unit 3 stores the area S of the brightness calculation unit 3.
Area information indicating the area is stored. This area information includes:
The values of (a, b, c) indicating the number in the x, y, and z directions, and the range (X-1x+), ( y-, y-), (z-, z and ゛) are stored. In addition, the initial values of these area information are stored in the initial storage means 40 as the range of the initial area So of each brightness calculation section 3. Further, in the brightness calculation units 3 existing on the outer periphery of the three-dimensional array, the brightness calculation units 3 may not be connected by the mutual means 31. Therefore, whether or not the luminance calculation section 3 is actually connected in each direction connected by the mutual communication means 31 is stored in the area information storage means 33 as presence/absence information.

These area information are input from the information input means 6,
It is transmitted to each brightness calculation unit 3.

FIG. 12 is an explanatory diagram showing the process of transferring information on the light ray R from the initial light generation section 1 to the brightness calculation section 3. As shown in FIG.
will be transferred all at once. Information on the light ray R transferred from the initial light generation section 1 is inputted to the light ray information determination means 37 provided in each brightness calculation section 3 via the communication means 32. At the same time, the information on the assigned area S stored in the area information storage section 33 is read out by the light beam information determining means 37. The starting point position coordinates (SX, S
y, S, ) is set to the position where the ray R first enters the object definition space. Therefore, if this starting point position coordinates (S,.

If Sy, S, ) is included in the assigned area S, the light ray R will pass through the assigned area S first.

Therefore, the ray information determining means 37 uses the starting point position coordinates (S,,Sy,S,) of the ray R and the range (x-,
xya >, <y-, yya), (Z-.

z+) is compared.

X-≦S, (X+ y-≦Sy<y.

If all three conditional expressions 2- ≦ S z < z + are satisfied, the starting point position coordinates (S
,,Sy,S,> is included in the assigned area S, and the ray R
will pass through the assigned area S first. in this case,
Information on the light ray R is transferred from the light ray information determining means 37 to the light ray information storage means 34 and stored therein. Furthermore, if any of these conditional expressions does not hold true, it means that the light ray R is first incident on another assigned area S°. Therefore, information on the light ray R is not stored in this brightness calculation section 3. Through the above processing, information on the light ray R generated by the initial light generation section 1 is stored in the light ray information storage means 34 of the brightness calculation section 3 which is in charge of the first incident area.

FIG. 13 is an explanatory diagram showing a process of storing object information and light source information from the object information setting section 2 in the object information storage means 35 and light source information storage means 36 provided in the brightness calculation section 3. As shown in FIG. 13, all the object information and light source information stored in the object information setting section 2 are transferred to all the brightness calculation sections 3 via the connection line 5. The light source information storage means 36 provided in the brightness calculation section 3 stores all the light source information transferred via the communication means 32. Then, the object information storage means 35 provided in the brightness calculation section 3 stores all the object information transferred via the communication means 32.

FIG. 14 is an explanatory diagram showing the process of changing the area S in its duty by the brightness calculation unit 3. This enlargement process of the assigned area S is performed by moving the boundary surface of the assigned area S in parallel. As shown in FIG. 14, the load determination means 43 provided in the brightness calculation section 3 determines the number of light rays R stored in the light beam information storage means 37 as the load F of the brightness calculation section 3. In addition,
Although such a load determination method is used here for the sake of simplicity of explanation, various other load determination methods are also possible. Even if a method other than this is used, processing can be performed in the same way as in Habo. For example, the load determination means 43 measures the time each brightness calculation unit 3 is actually performing processing and the time it waits for information on the light ray R, and calculates the load of each brightness calculation unit 3 from these values. You may decide. The load F determined by the load determining means 43 in this way is
1, x-, x, y- of the brightness calculation unit 3.

Brightness calculation unit 3 connected in y, z-, z+ force directions (x
-), (x-), (y->, (y->).

(z-) and (zya), respectively. The direction determining means 44 is the brightness calculating section 3 (x-).

The load F (x-
), F (x+), F (y-), F (y-
), F (z-), and F (z+), only one F□8 is selected which is the largest. Then, that direction is determined as the enlargement direction, and a value D□8 indicating that direction is output. This value D1.1. X is an integer from 1 to 6, and x- respectively starting from 1.

The X+, y-, 'l+, Z-, and Z directions are shown.

At the same time, loads F(x-), F(x+), F(y-), F
(y4), F(z-), and F(z,), select only one minimum one, Fl. Then, that direction is determined as the reduction direction, and a value D n+ I indicating that direction is determined.
Output n. The value of D win is also an integer from 1 to 6 and indicates the same direction as D + sax. Values indicating the maximum direction and minimum direction determined by the direction determining means, respectively, are n□+D1ml. as the expansion direction and contraction direction of the area S in charge of the area changing means 47
Output to. At the same time, the minimum load value F1° determined by the direction determining means is output to the enlargement determining means 45. Further, the minimum load value F mlo determined by the direction determining means and the value D + mln indicating the direction of reduction are output to the reduction determining means 46 . Then, the expansion determining means 45 determines whether or not to expand the assigned area S by comparing it with the load F of each adjacent brightness calculation unit 3 as follows, and outputs the result dF□.

When F□, -F>TH dF,□=1 Otherwise dF□8=O TH: Positive threshold value set in advance through the information input section 6 As a result, when dF□8 is 1, the person in charge Set area S to value D□
Expand in the direction indicated by 8. Also, this result d
When F, . . . is O, the assigned area S is not expanded. The determination result dF of the responsible area S determined in this way is...
In response to this, if this value is 1, the area changing means 47 expands the range of the area S in its duty. This area changing means 47 is
A value Dw indicating the enlargement direction determined by the direction determining means 44
According to ax, first, from the area information storage means 33, the value of the area S in charge, . The range a in the direction indicated by is read out and stored. For example, if the value D 5aax is 1, then
In the case of 2, read out Xyu.

Next, a new range a° is determined as shown below.

When D,,,=1.3.5, a'==a-dSD,
,, when =2.4.6, a' = a + dSdS: amount of change set in advance through the information input section 6. The range a° obtained in this way is stored in the area information storage means 33.
, and expand the scope of the area S in charge. Further, the reduction determining means 46 determines the minimum value F of the load of each adjacent brightness calculation unit 3.
mln and the load F of the brightness calculation unit 3 are compared. Then, the reduction determining means 46 converts the range a of the area S in charge of the brightness calculation unit 3 in the reduction direction indicated by the value D rm I n determined by the direction determining means 44 to the area information storage means 33.
Read from.

At the same time, the initial area S of the brightness calculation unit 3 in the reduction direction.

The range a(, ) is read from the initial area storage means 40.

And these range a and range a. Compare with. Here, the reason why range a and range ag are compared is that the assigned area S is the initial area S in the reduction direction. This is to prevent it from becoming smaller. That is, when a = aQ, the assigned area S is the initial area S in the reduction direction.

Since it is equal to , no reduction is performed. Also, a #
When a□, the assigned area S has been expanded in the reduction direction, so even if it is reduced in the reduction direction, the initial area S
There is no possibility that the size will be smaller than o. In this way, based on the comparison between range a and range a (,), it is possible to prevent the assigned area S from being reduced smaller than the initial area So in the reduction direction. Comparison results with load F of calculation unit 3 and range a and range a.

Based on the comparison result with
> dFmln when TH and a'#aQ
= 1 otherwise dF, 1. = O TH: Positive threshold value set in advance through the information input unit 6. When the result dF+++lr+ is 1, the assigned area S is reduced in the direction indicated by the value Dmin. Moreover, when dF,I is 0 as a result, the area S in charge is not reduced. In response to the determination result dFffiIn of the assigned area S determined in this way, if this value is 1, the area changing means 47 reduces the range of the assigned area S. The area changing means 47 first reads out the range a in the direction indicated by the value Dmln of the assigned area S from the area information storage means 33 according to the value Dmln indicating the reduction direction determined by the direction determining means 44. memorize it. For example, the value D m
If l n is 1, read out X-, and if n is 2, read out X or.

Next, a new range a' is determined as shown below.

When D mln = 1, 3, 5, a' = a
+dSD mln = 2, 4, 6, a'
=a−dSdS: Positive change amount set in advance through the information input unit 6 The range a° thus obtained is stored in the area information storage means 33.
, and reduce the range of the responsible area S. By performing such processing for changing the assigned areas S, it is possible to increase the number of objects included in each assigned area S and the number of light rays passing through, thereby increasing the calculation amount of each brightness calculation unit 3. be able to. At the same time, it is possible to reduce the load on the adjacent brightness calculation unit 3 which is responsible for the area adjacent to the enlargement direction indicated by the value Dmln, and the adjacent brightness calculation unit 3 which is responsible for the area adjacent to the reduction direction indicated by the value Dmln. The load on the calculation unit 3 can be increased. Therefore, it is possible to average out the total amount of calculations and redistribute the load appropriately.

FIGS. 15(a) and 15(b) are explanatory diagrams showing a method of transferring information on the light ray R between the brightness calculation units 3. As shown in FIG. 15(a), changing the assigned area S causes the boundary surfaces of the areas to overlap. Moreover, as shown in FIG. 15(b),
The connection between the brightness calculation units 3 via the mutual communication means is fixed. Therefore, in the case shown in FIGS. 15(a) and 15(b), the information on the light ray R incident on the responsible area Sa from the responsible area sb is directly transmitted from the brightness calculation unit 3a via the mutual communication means 31. It cannot be transferred to the calculation section 3b. Therefore, such information on the light ray R is first transmitted from the brightness calculation section 3a to the brightness calculation section 3C via the mutual communication means 31.
will be forwarded to. The information on the transferred light ray R is temporarily stored in the light ray information storage means 34 of the brightness calculation section 3C. In order to perform such a transfer process, the information on the light ray R stored in the light ray information storage means 34 of each brightness calculation section 3 is first read out to the light ray information determination means 37. This light ray information determining means 37 determines the starting point position coordinates (SX, S,
, S, ) and the range (X-, x4), (y-, y4>, (z-) of the assigned area S read from the area information storage means 33
, z+), and performs the following processing.

(2) When S<x-, information on the light ray R is transferred to the brightness calculation section 3 connected in one direction of X via the mutual communication means 31, and the process proceeds to (2).

■ SX≧X. At this time, via the mutual communication means 31,
The information on the light ray R is transferred to the brightness calculation unit 3 connected in the Transfer to brightness calculation unit 3 and go to ■.

■ When Sy≧y+, via the mutual communication means 31,
y information about ray R. Transfer to the brightness calculation unit 3 connected to the direction and go to ■.

(2) When S<z-, the information on the light ray R is transferred to the brightness calculation section 3 connected in one direction of Z via the mutual communication means 31, and the process proceeds to (2).

■ When S2≧24, via the mutual communication means 31,
Transfer the information on the light ray R to the brightness calculation unit 3 connected in the 2+ direction and proceed to ■.

(2) End If the information on the ray R is transferred between the brightness calculation units 3 in this way, the information on the ray R can be processed by the correct brightness calculation unit 3.

FIG. 16 is an explanatory diagram showing a method of calculating the brightness of each pixel by the process of determining the intersection between a light ray and an object in the brightness calculation unit 3. As shown in FIG. 16, the information on the ray R stored in the ray information storage means 34 is first stored in the ray information determining means 37.
is read out. As a result of the determination process in the light ray information determination means 37, information on the light ray R that has not been transferred to the adjacent brightness calculation section 3 is sent to the three intersection determination means. This intersection 1'II determining means 39 performs an intersection determination process between the object included in the area S in its duty and the light ray R. for that.

The object information determination means 38 stores the ranges (x-, x,), (y-, y-), (z-,
zl) and the range of the circumscribed area of each object i (x+-, X1+)
+ (3'l-+ y++)+ (zl-, z++
) to determine whether each ¥JIJ body i is included in the assigned area S.

FIGS. 17(a) and 17(b) show the area S in charge of the brightness calculation unit 3.
FIG. 4 is an explanatory diagram showing a comparison process between the object information and the circumscribed area of the object information. As shown in FIGS. 17(a,) and 17(b), when the assigned area S and the circumscribed area have no common part, at least one of the following conditional expressions holds true.

X-≧Xμ It is determined whether or not the area has a common part. As a result, if there is a common part, it is determined that the object i is included in the assigned area S, and information about the object i is transferred to the three intersection determination means. If they do not have common parts, they will not be transferred.

Through the above processing, among the object information stored in the object information storage means 35, only the object information included within the assigned area S is transferred from the object information determination means 38 to the three intersection determination means. Then, the intersection determination means 39 performs an intersection determination process between the object i transferred from the object information determination means 38 and the light ray R.

゛ As a result, for the ray R that does not intersect with the object, the intersection of the ray R and the boundary surface of the assigned area S is first found.

From this point of intersection, the region S° into which the light ray R will next enter is determined, and the direction in which the information of the light ray R should be transferred is determined.

Information on the light ray R is transferred via the mutual communication means 31 to the brightness calculation unit 3 in the determined direction. At this time, the starting point position coordinates of the light ray R are changed to the position coordinates of the obtained intersection point. As a result, the starting point position coordinates of the light ray R will be included in the area where the light ray R should enter next. The information on the light beam R thus transferred is read out from the mutual communication means 31 and stored in the light beam information storage means 34. Also, if the ray R intersects the object, new rays R' and RL
When the light beam R° and the light beam RL are generated, information on the light beam R° and the light beam RL is stored in the light beam information storage means 34. Such intersection determination processing is shown in each of the aforementioned papers and FIG. 2. When the brightness I of the light ray R is determined by this process, the brightness ■ is added to the pixel p(i, j) of the image storage unit 4 indicated by the information of the light ray R via the communication means 32. Ru. The synthesis of the image P is completed when all the information on the light rays R stored in the light ray information storage means 34 of each brightness calculation section 3 has been processed by the above-described intersection determination process.

〔Effect of the invention〕

In the object image synthesis device of the present invention, the shape of the area in charge of each brightness calculation section is a rectangular parallelepiped, and each surface of the rectangular parallelepiped is perpendicular to the coordinate axis. Therefore, it is very easy to determine the intersection between the boundary surface of the assigned area and the light beam. Therefore, when a light ray passes through the assigned area, it is possible to determine the area to which the information of this light ray should be transferred with a much smaller amount of processing than in the past. Further, the shape of the assigned area is changed by moving the boundary surface perpendicular to each coordinate axis in a direction parallel to the coordinate axis. Therefore, even if the shape of the area in charge is changed, the area in charge is kept in the shape of a rectangular parallelepiped, so the above-mentioned effects are not impaired. In this way, since the amount of processing required when changing the shape of the assigned area is small, it is possible to sufficiently obtain the effect of redistributing the load of each brightness calculation unit by changing the shape of the assigned area.

[Brief explanation of the drawing]

Figure 1 (a) is an overall configuration diagram showing the entire object image synthesis device, Figure 1 (b) is a configuration diagram showing the detailed configuration of its brightness calculation section, and Figure 2 is a diagram showing the detailed configuration of the brightness calculation section of the device. FIG. 3 is an explanatory diagram showing information on the ray R that should be set when the ray R is generated. FIG. 5 is an explanatory diagram showing the object information set in the object information setting section 2, FIG. 6 is an explanatory diagram showing the circumscribed area of a sphere as an object, and FIG. 7 is an explanatory diagram showing the object information set in the object information setting section 2. An explanatory diagram showing information on the light source to be set, FIG. 8 is an explanatory diagram showing a method of combining a plurality of brightness calculation units 3 into a three-dimensional array, and FIG. FIGS. 10 and 11 are explanatory diagrams showing the contents of area information indicating the assigned area S of the brightness calculation unit 3, and FIG. FIG. 13 is an explanatory diagram showing the process of transferring information of the light ray R from the brightness calculation unit 3 to the brightness calculation unit 3. FIG. FIG. 14 is an explanatory diagram showing the process of storing object information and light source information. FIG. 14 is an explanatory diagram showing the process of changing the area S in charge of the brightness calculation unit 3. FIGS. 15(a) and (b)
FIG. 16 is an explanatory diagram showing a method of transferring information of the light ray R between the brightness calculation units 3, and FIG.
FIGS. 17(a) and 17(b) are explanatory diagrams showing the process of comparing the area S in charge of the brightness calculation unit 3 with the circumscribed area of the object information. In the figure, 1... Initial ray generation section, 2... Object information setting section, 3
, 3 a , 3 b , 3 c , 3 d ・
- brightness calculation unit, 4... picture width storage unit, 5... connection line,
6... Information input section, 31... Mutual communication means, 32.
...Communication means, 33...Area information storage means, 34...
・Light ray information storage means, 35...Object information storage means, 3
6... Light source information storage means, 37... Light beam information determination means, 38... Object information determination means, 3... Intersection determination means, 40... Initial area storage means, 43... Load Determining means, 44...Direction determining means, 45...Enlargement determining means, 46...Reduction determining means, 47...Region,)j1
C' I 5 Cbn Kaya Otsu
Figure $ /θ times i no 4 times (a) (b) 15th TM

Claims (1)

[Claims] The above image synthesis is performed using a ray tracing method that traces the path of the light ray from the light source to the viewpoint in the opposite direction, performs intersection determination processing with the object, and calculates the brightness of each pixel that makes up the image that should display the above object. an initial ray generation unit that generates information on a plurality of rays passing through each pixel from the viewpoint;
an object information setting unit that sets information about the object; a ray passing through one area of a plurality of areas generated by dividing the space defined as the object; and the area in charge of the object; consists of a plurality of brightness calculation units that calculate the brightness of the pixel by performing intersection determination processing with objects included in the image, and an image storage unit that stores the brightness calculated by the brightness calculation units as the image. In the object image synthesis device, the brightness calculation unit includes area information storage for storing a range of an area in charge of the brightness calculation unit among a plurality of areas generated by dividing the object definition space by a plane perpendicular to the coordinate axes. means, initial area storage means for storing the range of the area in charge given as an initial value in the brightness calculation unit as the range of the initial area, load determination means for determining the load of the brightness calculation unit, parallel to each coordinate axis. mutual communication means for performing mutual communication between the adjacent brightness calculation section and the brightness calculation section that are in charge of areas adjacent to the area in charge in a direction; and a load on the adjacent brightness calculation section obtained through the mutual communication means. The direction of the area in charge of the adjacent brightness calculation unit where the load is the maximum is determined as the expansion direction of the area in charge of the brightness calculation unit, and the direction of the area in charge of the adjacent brightness calculation unit where the load is the minimum is determined as the area in charge of the brightness calculation unit. and a direction determining means that determines the reduction direction of the brightness calculation section and the load of the adjacent brightness calculation section in which the load is the maximum, and compares the load of the brightness calculation section with the load of the brightness calculation section, and determines the brightness calculation section in the enlargement direction determined by the direction determination means. expansion determining means for determining whether or not to expand the area in charge of the area, and comparing the load of the adjacent brightness calculation unit with the load of the brightness calculation unit where the load is the minimum, and further calculating the area stored in the initial area storage means. Comparing the range of the initial area and the range of the area in charge stored in the area information storage means, and determining whether or not to reduce the area in charge in the reduction direction determined by the direction determining means based on the comparison results. a reduction determining means for determining, enlarging the area in charge in the enlargement direction determined by the direction determining means based on the decisions of the enlargement determining means and the reduction determining means; An object image synthesis device comprising: area changing means for changing the range of the area in charge stored in the area information means in order to reduce the area in charge.